Miniature switch with contact aligned detent structure



June 7, 1966 B. A. PAINE 3,255,319

MINIATURE SWITCH WITH CONTACT ALIGNED DETENT STRUCTURE Filed Aug. 26, 1964 INVENTOR Bup firm E ATTORNEYS United States Patent 3 255 319 MINIATURE SWITCH WI'IH CONTACT ALIGNED DETENT STRUCTURE Bud A. Paine, San Gabriel, Calif., assignor to Spectrol' This invention relates generally to switches and more particularly to miniature multi-position rotary switches of the type which are particularly adaptable for use in such applications as printed circuits.

Prior art rotary switches, although they have been quite effective for the purposes intended, have been found to have several inherent limitations. All known prior art rotary switches of the type here involved operate by having the rotary contact element travel through a single continuous plane, the surface of which remains parallel with the plane defined by the contact surface of the stationary contacts.

As the rotary contact element traveled in the single plane above referred to, the contact point thereof was caused to slide not only across the stationary contact with which it was desired to establish electrical continuity, but also to travel across the base material in which the stationary contact was embedded or otherwise held. Usually,

the base material was softer than the electrical contact material. Under these circumstances, in order to prevent undue wear upon the softer base material, it was 'required that a relatively light contact pressure be utilized. Under these circumstances, the rotary contact element could intermittently make and break contact with the stationary contact element under severe operating conditions. Furthermore, the light contact pressure in some instances resulted in high resistance contact being made.

As the rotary contact element traveled in the single plane above referred to, it was not at all uncommon for arcing to occur as the rotary contact either made or broke electrical-continuity with the stationary contact. This resulted since the rotary contact element relatively slowly contacted and broke electrical connection with the stationary contacts. 7

Accordingly, it is an object of the present invention to provide a miniature multi-position rotary switch which is inexpensive, extremely small, and yet rugged in construction and which overcomes the prior art problems above referred to.

It is another object of the present invention to provide a miniature multi-position rotary switch which has a relatively long lifetime, in which low contact resistance is established between the stationary and the rotary contacts, and in which arcing between contacts is substantially eliminated.

It is another object of the present invention to provide a miniature multi-position'rotary switch which permits use of contact pressures not heretofore possible, and which eliminates shorting between stationary contacts by the rotary contact during operation of the switch.

It is another object of the present invention to provide a miniature multi-position rotary switch which has a sealed housing thus preventing the entry of foreign contaminants into the working portions of the switch.

Additional objects and advantages both as to organization and method of operation of a miniature rotary multiposition switch in accordance with the present invention will become more apparent from a consideration of the following description taken in conjunction with the accompanying drawing which is presented by wayof example only and is not intended as a limitation upon the scope of the appended claims, and in which:

FIG. 1 is a perspective view, partially cut away, of a Patented June 7, 1966 multi-position rotary switch in accordance with the present invention;

FIG. 2 is a cross-sectional view of a switch in accordance with the present invention taken about the lines 2-2 of FIG. 1;

' FIG. 3 is a top elevational view of a switch in accordance with the present invention and with the cover re moved and certain parts thereof broken away;

FIG. 4 is a perspective view of the rotary contact element utilized in a preferred embodiment of the present invention; and

FIGS. 5 and 6 are fragmentary views illustrating the rotary contact element in two different operational posi- .tions.

A multi-position rotary switch in accordance with the present invention includes one or more stationary contact elements positioned internally of a switch housing. A plurality of lands and grooves are disposed adjacent the stationary contact element in such a manner that there is a groove aligned with each stationary contact. 'A rotary contact element is movably supported within the housing and is in sliding engagement with the lands and grooves in such a manner that as the rotary contact element is rotated, it alternately engages a land and a groove and effects electrical continuity only during the time that the rotary contact element is resident within a groove that is aligned with a given stationary contact element.

Referring now to the drawing and more particularly to FIG. 1 thereof, there is disclosed generally at 10 a rotary switch in accordance with the present invention. As is illustrated, the rotary switch 10 includes a housing 11 which consists of a base member 12 and a cover 13. The cover 13 is coated on the inner surface thereof with a re silient lining material 14 such, for example, as silicone rubber. As is illustrated, the cover 13 along with the liner 14 is crimped into a sealing engagement with the lower peripheral surface of the base member 12 and also effects a seal about the rotary shaft 30 thus precluding entry of foreign matter into the housing. A plurality of electrically conductive pins 15 extend through the base member 12 and form pads or stationary switch contacts internally within the cavity formed by the housing 11, such, for example, as is illustrated at 16 and 17.

A rotary contact member illustrated generally at 20 is disposed within the cavity formed by the housing 11 and is driven by a shaft 30. Although the shaft may be driven in any manner which is desired, either mechanically or electrically, as is illustrated in FIG. 1, the shaft 30 is provided, in an exposed surface thereof, with a kerf 31 which is adapted to receive an adjusting tool such as a screwdriver for rotation of the shaft 30 and consequently the rotary contact member 20.

A plurality of lands and grooves illustrated generally at are disposed within the cavity formed 'by the housing 11 in such a maner that the rotating contact 20 is in sliding engagement therewith. As a result thereof, as the rotating contact is moved by rotation of the shaft 30, the contact element 21 of the rotatiing contact 20 oscillates up and down, as viewed in FIG. 1, and during the time that it is resident within a groove which is aligned with one of the pins 16 or 17, for example, electrical continuity is established through the rotary contact element 20 with the respective pin member. This will become more fully understood from the subsequent description and illustrations.

Referring now more particularly to FIGS. 2, 3 and 4, the various details of the multi-position miniature rotary switch in accordance with the present invention are more clearly illustrated. As is therein shown the rotary contact member illustrated generally at 20 is rotatably supported upon a center post 22 and is maintained in engagement with a shoulder 23 extending outwardly thereon as 'ber.

a result of pressure which is applied through the shaft member 30 by means of the cover 13 and the liner 14 thereof. The center post 22 is constructed of electrically conductive material and is in electrical contact with a center stationary contact pin 24 which extends through the base 12 of the housing 11.

As is more clearly illustrated in FIG. 4, the rotary contact member is constructed of a unitary metallic mem- The rotary contact 20 defines an aperture 25 centrally thereof for receiving the center post 23. The aperture 25 is defined by an annular member 26 which surrounds the center post 22 and rests upon the shoulder 23 to establish electrical contact as above described. A wishbone shaped portion 27 is bent downwardly along the line 28 and the contact element 21 is provided as a part thereof. The contact element 21 is dimpled to provide a concave surface 21a and a convex surface 21b as is illustrated, the convex surface 2112 being utilized, in part, to make electrical contact with the stationary contacts disposed internally within the housing of the switch.

Opposite the electrical contact 21 there is defined an opening or recess 29 within the rotary contact element 20 which opening includes spring locks 29a and 29]) which are used in conjunction with the shaft member 30.

As is illustrated, the shaft member 30 consists of a substantially disk-shaped member 32 of electrically nonconductive material having a cylindrical portion 33 rising upwardly therefrom. The cylindrical portion 33 extends through an opening 18 formed in the cover 13 and liner 14 of the housing. The cylindrical portion 33 thus is exposed to the exterior of the housing and has the kerf 31 formed therein for receiving the desired adjusting tool as above described. The disk-shaped shaft 32 defines a recess 34 centrally thereof which receivesthe center post 22. A driver member such as protrusion 35 extends downwardly from the lower surface of the disk 32 and engages the opening 29 in the rotary contact member 20 and functions as a driving member therefor. The spring locks 29a and 2% are forced outwardly as the protrusion 35 is inserted within the opening 29 and thus through spring tension lock the rotary contact'm'ember 20 in place upon the protrusion 35.

A plurality of lands and grooves are formed by being molded integrally with the base 12 of the housing 11. The lands and grooves are disposed between the stationary contacts and the center post 22. It should however be expressly understood that the lands and grooves may-be positioned at any point which is desired. F or example, the stationary contacts and the lands and grooves may be reversed in position without changing the spirit or the scope of the present invention. As is more readily seen by viewing FIG. 3 there is provided a groove between each adjacent pair of lands and each groove is aligned with a stationary contact. For example, as is illustrated by the two adjacent lands 41 and 42 the groove 43 is aligned with the stationary contact 44. It should also be recognized from viewing FIG. 3 that each of the lands is disposed upon a radius of the rotary switch which is between adjacent stationary contacts. For example, a radius 46 of the switch extends between the stationary contacts 44 and 45. It is upon this radius 46 that the land 41 is located. As is more readily seen by viewing FIGS. 1 and 3, each of the lands is formed by a pair of inclined surfaces which are joined at the top, for example, see land 41 in FIG. 3 which has inclined surfaces 47 and 48. The groove 43, for example, is formed by the inclined surface 47 on the land 41 and the inclined surface 49 on the land 42 being in opposed relationship. During the time that the contact element 21 on the rotary contact member 20 resides within 'the groove 43 electrical contact is made with the stationary contact 44.

It should thus be seen that as the shaft 30 is rotated, the driver 35 causes the rotary contact member 20-to rotate which in turn moves the contact element 21 into alternate positions successively either in a groove or upon a land as illustrated respectively by the dashed position A and the solid position B shown for the contact element 21 in FIG. 2. These two positions are illustrated more clearly in FIGS. 5 and 6 to which reference is hereby made.

As is shown more particularly in FIG. 5, the convex surface 21b of the contact element 21 is resting within a groove 51 formed by the inclined surfaces 52 and 53 of adjacent lands 54 and 55 respectively. In the position as is illustrated, the convex surface 21b not only rests within the groove 51 but also conforms to the curvature of the inclined surfaces 52 and 53. As the rotary contact is moved, for example, toward the right as viewed in FIG. 5, the convex surface 21b slides along the inclined surface 53 in an upward direction and immediately removes the convex surface 2112 from the groove 51 thus breaking electrical engagement with the stationary contact 56. It should from this description be readily understood that the surfaces 52 and 53 operate very much in the nature of cams and the electrical contact 21 operates very much in the nature of a cam follower. As the electrical contact 21 is rotated further toward the right as viewed in FIG. 5, it will in its opposite extreme position be upon the top of the land 55 as is illustrated in FIG. 6. In this position, upon further rotation of the electrical contact 21 the convex surface 21b thereof will engage the inclined surface 57 on the land 55 and as a result of the spring action of the rotary contact member 20, the contact element 21 will be very rapidly moved into engagement with the groove 58 where once again electrical contact is made with a stationary contact.

As the contact element 21 moves downwardly along the inclined surface 57 toward engagement with the stationary contact aligned with the groove 58, it should be noted that the electrical contact convex surface 21b first makes an initial engagement with the stationary contact and then as a result of the spring tension imparted to the contact, moves slightly outwardly as viewed in FIG. 2. As a result of this movement the convex surface 21b scrubs the surface of the stationary contact, thus, in all cases, always insuring a clean and very low resistance contact.

As should become apparent from the foregoing description, the electrical contact element 21 formed as a part of the wishbone shaped part 27 of the rotary contact member 20 is bent downwardly from a plane established by the annular member 26 and as a result of this bending, a contact pressure of a relatively large and significant amount is established between the electrical contact 21 and the stationary contacts positioned concentrically about the center post 22. It should become further apparent that as the shaft 30 is rotated by the adjusting tool 31, the operation of the rotary contact member is such that electrical continuity is established in a successive manner from switch position to switch position as long as rotary motion is imparted to the rotary contact member. As a result of the high contact pressure, positive contact is established in a very fast manner and the electrical contact is also broken in a fast manner as the convex surface of the electrical contact 21 rides upon the cam surfaces formed by the inclined surfaces of each of the lands.

There has thus been disclosed a miniature multi-position rotary switch which is rugged, relatively inexpensive to manufacture and provides excellent switching characteristics heretofore not realized in switches of similar types.

What is claimed is:

1. A multi-position miniature rotary switch comprising:

a housing defining a cavity therein;

a plurality of stationary contact elements positioned within said cavity;

a plurality of lands and grooves adjacent said stationary contact elements,

a groove being aligned with each stationary contact element,

a rotary contact element movably supported within said cavity and being in engagement with said lands and grooves; and

actuating means for rotating said rotary contact element, whereby upon rotation thereof said rotary contact element engages a stationary contact only during that time said rotary contact element is resident within the aligned groove.

2. A multi-position miniature switch as defined in claim 1 in which said housing includes a base and a cover, said cover being internally lined with a resilient material in sealing engagement with said base.

3. A multi-position miniature switch as defined in claim 1 in which said actuating means is a shaft member engaging said rotary contact element and extending through said housing.

4. A multi-position miniature switch comprising:

an electrically non-conductive base member;

an electrically conductive post extending upwardly from said base member;

a plurality of discrete electrically conductive contact elements on said base disposed substantially circularly about said post;

a plurality of alternate lands and grooves radially disposed about said post,

one of said grooves being aligned with each of said contact elements,

one of said lands being disposed on a radius extending between each adjacent pair of contact elements;

resiliently deformable contact means disposed in engagement with said lands and grooves;

electrically conductive means interconnecting said deformable contact means and said post; and

actuating means for effecting relative movement between said deformable contact means and said discrete contact elements,

whereby electrical continuity iseffected between successive discrete contact elements and said post only during residence time of said deformable contact means in that groove aligned with each said discrete contact element.

5. A multi-position miniature switch as defined in claim 4 in which said lands and grooves are formed in.- tegrally with said base member and form therewith a unitary member.

6. A multi-position miniature switch as defined in claim 4 in which said lands and grooves are disposed between said post and said discrete contact elements.

7. A multi-position miniature switch as defined in claim 4 in which said actuating means is electrically energized to bring said deformable contact means and said discrete contact elements into mutual engagement in discrete steps.

8. A multi-position miniature rotary switch comprising:

a housing defining a cavity therein andincluding an electrically non-conductive base member;

an electrically conductive post member centrally disposed within said cavity and extending through said base member in fixed relationship therewith;

a plurality of electrically conductive pin members extending in fixed relationship through said base member and providing a plurality of spaced apart stationary electrical contacts concentrically disposed with said post member;

a plurality of alternate lands and grooves radially disposed about said post,

one of said grooves being aligned with each of said contact elements,

one of said lands being disposed on a radius extending between each adjacent pair of contact elements,

each of said lands being interconnected with the groove on each side thereof by an inclined surface,

said lands and grooves being formed on said base member;

a rotatable contact member disposed upon said post and in electrical contact therewith and including,

a concave-convex portion having sides which ongage adjacent inclined surfaces and a bottom which engages one of said stationary contact elements when said rotatable contact member elfects electrical continuity between said post and one of said stationary contact elements,

a central aperture for receiving said post member,

and

a slot for receiving drive means; and

actuating means having drive means received within said slot for rotation of said rotatable contact member.

9. A multi-position miniature rotary switch as defined in claim 8 in which said actuating means is a shaft having a bore, said post being received within said bore.

10. A multi-position miniature rotary switch as defined in claim 9 in which said rotatable contact member is formed from a unitary metallic member and in which i said housing includes a base member and a cover, said rotatable contact member being held in electrical contact with said post member by said cover being held against said shaft.

No references cited.

KATHLEEN H. CLAFFY, Primary Examiner. 

1. A MULTI-POSITION MINIATURE ROTARY SWITCH COMPRISING: A HOUSING DEFINING A CAVITY THEREIN; A PLURALITY OF STATIONARY CONTACT ELEMENTS POSITIONED WITHIN SAID CAVITY; A PLURALITY OF LANDS AND GROOVES ADJACENT SAID STATIONARY CONTACT ELEMENTS, A GROOVE BEING ALIGNES WITH EACH STATIONARY CONTACT ELEMENT, A ROTATY CONTACT ELEMENT MOVABLY SUPPORTED WITHIN SAID CAVITY AND BEING IN ENGAGEMENT WITH SAID LANDS AND GROOVES; AND 